A laboratory procedure to evaluate the acid producing potential of coal associated rocks

Abstract Pre-mine planning to minimize or eliminate the production of acid mine drainage (AMD) necessitates that the acid producing potential of each of the lithic units encountered in mining be evaluated. Presently used techniques to predict acid production are generally inadequate primarily because they are based upon unsubstantiated assumptions and because they do not provide the capability of determining the rate at which acid will be produced. This paper describes an experimental bench top procedure which will determine the rate and amount of acid that a rock will produce upon being exposed to the atmosphere. This procedure has been verified by predicting the acid production response of a 350 ton simulated backfill of coal associated rocks exposed to natural weathering conditions with better than 90% confidence.